bypassing Cat ECUs

I don't have the answer but would be interested in knowing the error code you got, if any. I installed HyperFlows a short time ago and have had a blinking "slow down" light since shortly after - starts blinking immediately on startup so excess heat isn't the cause. Had Tubis on before the H-F's. Thinking of headers in the future. One (maybe both separately, can't recall right now) had been replaced according to the previous service history.

Cheers

 

They are suposed to be shorted. Pull out the thermo couples, put the multimeter probes to the connector then set it to DCV. Then get a propane torch to the probe and watch your multimeter voltage reading they should put out about 1v don't heat them too much.

I would swap the cat ecu's around to see if the error continues. Also inspect the potting on the ECU's make sure there are no cracks on the potting.

 

I'd rather have new thermocouples (cheap sensor part) in order to keep the warning circuitry (Hyper-Flows can overheat and cause fires, too, after all).

A faulty thermo sensor or shorted wires would probably yield 10 ohms or less when the cats are cold. The Ferrari system is normally expecting 350 ohms between those two wires up to 800 ohms.

When the resistance falls below 350 ohms, the exhaust ecu reports an overheated cat, but something less than 10 ohms would probably be a fault/short instead.

 

Frenchie, Do a search on the topic you'll find a ton of chatter. Short story tho pull the probes, ECUs and the lights bulbs in the dash and you'll be good to go. regards, Vern

 

I was having a problem with on bank of cylinders 1-4 on my 348.
sometimes the light would come on solid and a short while later it would shut down the bank.
this happened twice. I decided to swap sides with the ECU. I did see the epoxy separtated from the plastic on the bank that was giving me problems so I put some high temp sealer on it. I did notice also that the epoxy on one ECU was like a greenish color and the one side that was OK was black. Don't know if that
has any bearing on the problem.
I do know that BOTH thermocuples had a reading of 5 ohms when cold.
are you certain that they should have a reading of around 380 ohms when cold?
I'm interested in knowing what others have measured.
either mine are good or trash, but I'd suspect I'd be having all kinds of problems
because they're both under 10 ohms.

 

Thanks. The other problem that I have with the information that I was quoting above is that a "thermo couple" is supposed to generate a voltage from heat, whereas a "thermo sensor" is typically a resistance measurement that varies with temp.

It makes me call into question the whole 350 ohms to 800 ohms = good claim. We should be looking at voltage, I bet, rather than resistance.

 

Yes, "thermocouples" generate a voltage with heat.

 

Bowing...I'm not worthy, I'm not worthy!

 

Please post the volts vs temp measurements that you get from cold to hot.